The present invention relates to an N-substituted maleimide polymer composition which has excellent thermal resistance, resistance against impact strength, mechanical strength and moldability.
It has hitherto been known that a resin having improved thermal resistance is prepared by copolymerizing an N-substituted maleimide with other vinyl monomers. For example, Japanese Patent Publication No. 9753/1968 discloses that a copolymer of phenyl maleimide and methyl methacrylate is useful for a molding material, and Japanese Patent Publication No. 12433/1969 discloses that a copolymer of vinyl chloride and a maleimide compound is useful for a molding material. "KOBUNSHI KAGAKU", Vol. 28., Page 330 (1971) and other publications disclose processes for preparing homopolymers of N-substituted maleimide and that the thus prepared N-maleimide polymers have resistance to extremely high temperature.
However, the thermal resistance of the known copolymer of the N-substituted maleimide and the vinyl monomer is still unsatisfactory. Although the known N-substituted maleimide copolymer has resistance to high temperature, it is extremely brittle and only has low mechanical strength, such as resistance against impact strength or tensile strength, so that it cannot be used as a molding material.